With technical advances and energy efficiency improvements occurring all the time, how can you choose the right combination equipment for your home? In this section we introduce you to elements of gas central heating system and the options that are available.
The boiler is the single most expensive item in the system. It is therefore important that it is sized to cope with the needs of your home. The efficiency of your boiler impacts directly on the running cost, the less efficient the more gas you will burn. Modern condensing boilers have been designed to increase efficiency by conserving the energy from high temperature flue gases, which were previously vented to the atmosphere. This process increases efficiency from 60% to over 90%. If your boiler is more than 10 years old it is likely that you have a low efficiency boiler and you should consider replacing it. Modern boilers have also been getting smaller, can be wall mounted and can fit neatly in most locations with less obtrusive pipework.
Additionally, boilers account for around 60% of the carbon dioxide emissions in a gas heated home and by fitting a new condensing boiler you will significantly cut your home’s carbon dioxide emissions and could save as much as £275 a year.
There are two ways of supplying hot water from your boiler.
Boiler and Hot water storage – This is the traditional method of supplying hot water where the boiler indirectly heats water in a storage tank. This can be less efficient since heat loss from the cylinder occurs if the water stands for long periods, however large amounts of water can be stored for delivery. This system is more suitable for family homes where the demand for hot water is greater. Various storage systems can be used but the most common are gravity fed and pressurized cylinders. The latter is preferable in larger properties where delivery can be required at a number of locations simultaneously.
Combination or Combi Boiler – This is a condensing boiler with an inbuilt heat exchanger which provides hot water by heating it on demand so you only heat the water that you use and you don’t need the space for a storage cylinder. You should be aware that, although improving, there are some drawbacks to the system that make it more appropriate for smaller properties with single or double occupancy.
The flow of hot water is less than that available through a traditional system and the delivery is significantly affected when more than one tap is opened. The temperature of the drawn water depends on the temperature of the cold feed and is therefore less hot in the winter.
When supplying water the boiler is diverted from providing central heating which can reduce background heat if water is drawn for a prolonged period.
Heating controls allow you to manage your system and could save you up to 17 per cent of your heating bill. You to choose when the heating is on, how warm it is, and where you want it.
A properly controlled heating system will have:
Programmer – This allows you to set the time your heating and hot water normally goes on and off during the day but also allows you to over-ride at any time.
Cylinder thermostat – cut off the boiler supply to the storage cylinder when the water reaches a preset temperature
Thermostatic radiator valves – these are designed to cut supply to individual radiators when the room temperature reaches a desired level and consequently reduces the demand on your boiler.
If your system has old style radiators you could increase the heat supplied to your rooms by installing new technology radiators that increase the heat radiated for a given rate of supply.
Combi boilers produce hot water at mains pressure, which means they are compatible to either a mains pressure balanced or thermostatically controlled shower. In contrast, when a regular boiler and cylinder is replaced with a combi boiler, any existing shower should be examined for suitability. This might be a pump assisted power shower, for example, designed for low-pressure systems.
If you are constantly losing pressure in the heating system you could try the following to establish the cause by:
Checking all visible joints including radiator valves and connections for obvious signs of leakage. There needs to be consideration to potential leaks to any under-floor pipe work.
Check that there is no water being discharged from the pressure relief valve (sometimes referred to as an overflow). This pipe usually goes from the boiler through to an outside wall and terminates outside. Check this for signs of dripping. If it is wet, this may mean that the pressure relief valve is faulty.
In either case, if your heating system keeps losing pressure to gain advice or help you should contact WRB Gas
A boiler timer is a basic device that allows you to set times for your central heating.
A boiler programmer allows you to set different times for heating and/or hot water.
A timer operates your heating system at the same times every day whereas a programmer allows different heating times for different days of the week to suit your lifestyle.
A room thermostat enables you to set the target temperature for a room. Room thermostats are usually best positioned in the hall or landing. They should be sited away from direct sunlight and clear of curtains and furniture.
Programmable room thermostats
A programmable room thermostat enables you to set different room temperatures for different times of the day and night. When set up correctly, a programmable room thermostat prevents the system from having to heat the house from a ‘cold start’. The control always maintains a temperature within the property and this ensures that the boiler is only ever ‘topping up’ the temperature in the home. As a guideline, target temperatures should be set at 21 C for comfort temperature and 15 C for economy temperature.